Séminaire

As an extension of Gabor signal processing, the covariant Weyl-Heisenberg integral quantization is implemented to transform  functions on the eight-dimensional  phase space (x,k) into Hilbertian operators. The x=(x^{\mu}) are space-time variables and the k=(k^{\mu}) are their conjugate wave vector-frequency variables. The procedure is first applied to the variables (x,k) and produces canonically conjugate essentially  self-adjoint operators.

Jan Harms
Title: Lunar Gravitational-wave Antenna

S.Katsanevas
Detecting Gravitational Waves at the Moon

We propose a physically sensible formulation of initial value problem for black hole perturbations in higher-order scalar-tensor theories. As a first application, we study monopole perturbations around stealth Schwarzschild solutions in a shift- and reflection-symmetric subclass of DHOST theories. In particular, we investigate the time evolution of the monopole perturbations by solving a two-dimensional wave equation and analyze the Vishveshwara’s classical scattering experiment, i.e., the time evolution of a Gaussian wave packet.

Astrophysical observations are largely based on electromagnetic signals still read with the Maxwellian massless and linear theory, possibly an approximation of a larger theory, as Newtonian gravity is for Einsteinian gravity in weak fields. Photons are the sole free massless particles in the Standard-Model (SM). Apart from massive formalisms (de Broglie-Proca, Bopp, Stueckelberg and others), the SM Extension dresses the photon of a mass dependent from the Lorentz-Poincaré symmetry violation.

The EU Underground Laboratories Workshop will be held at the Gran Sasso Laboratory, Italy, on April 28-29.

The Workshop aims to reinforce the network between EU Underground Laboratories in order to develop a strong synergy to face next generation experiments for rare events searches. The meeting will focus on reviewing the existing facilities and planned new ones for supporting research activities, strategy for collaboration and work load sharing, training and networking, interaction with the APPEC community.

The Second Joint ECFA-NuPECC-ApPEC Seminar (JENAS) will be held from May 3rd to 6th, 2022 in Madrid  
The seminar is a prestigious joint meeting of particle, nuclear and astroparticle physics scientific communities exploring synergies and highlighting recent achievements and challenges.

The participants represent scientists of the three communities, the funding agencies (important for our field) as well as big international projects and collaborations. 

After recalling the definition of a black hole and its basic properties (mass, angular momentum and area), the seminar will focus on links between black holes and gravitational waves. In particular black hole thermodynamics will be discussed in connection with gravitational wave emission, as well as the so-called black hole information paradox.

Contact kleyde@apc.in2p3.fr for zoom meeting details. 

In this seminar I will present the first direct numerical simulation of gravitational wave turbulence (Galtier & Nazarenko, PRL 127, 131101, 2021). General relativity equations are solved numerically in a periodic box with a diagonal metric tensor depending on two space coordinates only (Hadad-Zakharov metric) and with an additional small-scale

Gravitational wave (GW) standard sirens are well-established probes with which one can measure cosmological parameters, and are complementary to other probes like the cosmic microwave background or supernovae standard candles. I will focus on dark GW sirens, specifically binary black holes (BBHs) for which there is only GW data. Relying on the assumption of a source mass model for the BBH distribution, we consider four models that are representative of the BBH population observed so far.